/*
 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.webkit.graphics;

public class Ref {
    private final int id;
    private int count;

    public Ref() {
        count = 0;
        id = WCGraphicsManager.getGraphicsManager().createID();
    }

    public synchronized void ref() {
        if (count == 0) {
            WCGraphicsManager.getGraphicsManager().ref(this);
        }
        count ++;
    }

    public synchronized void deref() {
        if (count == 0) {
            throw new IllegalStateException("Object  " + id + " has no references.");
        }
        count --;
        if (count == 0) {
            WCGraphicsManager.getGraphicsManager().deref(this);
        }
    }

    public boolean hasRefs() {
        return count > 0;
    }

    public int getID() {
        return id;
    }
}
